NASA’s MESSENGER orbiter of Mercury ran out of fuel and crashed into Mercury on May 1, 2015, ending a very successful mission. The craft slammed into Mercury’s surface at about 8,750 mph and created a new crater on the planet’s surface.
MESSENGER’s demise went unobserved because the probe hit the side of the planet facing away from Earth, so ground-based telescopes were not able to capture the moment of impact. Space-based telescopes also were unable to view the impact, as Mercury’s proximity to the Sun would damage their optics.
MESSENGER had been in orbit more than four years and completed 4105 orbits around Mercury. Among its many accomplishments, the MESSENGER mission determined Mercury’s surface composition, revealed its geological history, discovered its internal magnetic field is offset from the planet’s center, and verified its polar deposits are dominantly water ice.
The movie below shows a NASA simulation of the spacecraft’s epic voyage.